Much of the previous art related to concentrated clear compositions containing ester and/or amide linked fabric softening actives and specific principal solvents relates to the formulation of mono-quaternary ammonium fabric softener actives and these are disclosed in U.S. Pat. No. 5,759,990, issued Jun. 2, 1998 in the names of E. H. Wahl, H. B. Tordil, T. Trinh, E. R. Carr, R. O. Keys, and L. M. Meyer, for Concentrated Fabric Softening Composition With Good Freeze/Thaw Recovery and Highly Unsaturated Fabric Softener Compound Therefor, and in U.S. Pat. No. 5,747,443, issued May 5, 1998 in the names of Wahl, Trinh, Gosselink, Letton, and Sivik for Fabric Softening Compound/Composition, said patents being incorporated herein by reference. The fabric softener actives in said patents are preferably biodegradable ester-linked materials, containing, long hydrophobic groups with unsaturated chains. Similar clear liquid fabric softening compositions are described in WO 97/03169, incorporated herein by reference, which describes the formulation of liquid fabric softening compositions using said specific principal solvents.
European Patent Application EP 0,803,498, A1, Robert 0. Keys and Floyd E. Friedli, filed Apr. 25, 1997 teaches that polyquaternary ammonium actives can be formulated into clear compositions. This application exemplifies clear compositions of polyquaternary actives at high principal solvent levels, typically 15% or more. It is economically desirable to formulate compositions with lower solvent levels, but formulating stable, isotropic, single-phase products at solvent levels at or below about 10%, particularly when using less preferred principal solvent systems is difficult.